How to get the difference of two querysets in Django?

Question

I have to querysets. alllists and subscriptionlists

alllists = List.objects.filter(datamode = \'A\')
subscriptionlists = Membership.objects.filter(member__id         


        

Answer 1

Well I see two options here.

1. Filter things manually (quite ugly)

diff = []
for all in alllists:
    found = False
    for sub in subscriptionlists:
        if sub.id == all.id:
            found = True 
            break
    if not found:
        diff.append(all)

2. Just make another query

diff = List.objects.filter(datamode = 'A').exclude(member__id=memberid, datamode='A')